R CMD install error

I am just doing my first steps in building an R package with C code on  
my Mac.
I get the same warning Duncan mentioned in his last message.
ld: warning, duplicate dylib /Developer/SDKs/MacOSX10.4u.sdk/usr/local/ 
lib/libgcc_s.1.dylib
Where can I find information on how to solve this problem?

--
Erich Neuwirth
Didactic Center for Computer Science and Institute for Scientific  
Computing
University of Vienna